Hydrotherapy: Water has been used medicinally for thousands of years, with traditions rooted in ancient China, Japan, India, Rome, Greece, the Americas, and the Middle East. There are references to the therapeutic use of mineral water in the Old Testament. During the Middle Ages, bathing fell out of favor due to health concerns, but by the 17th century, “taking the waters” at hot springs and spas became popular across Europe (and later in the United States)